Photovoltaic solar panel for attachment to a roof tile and method of manufacture thereof

ABSTRACT

A photovoltaic solar panel for attachment to a roof tile can include a printed circuit board, a plurality of photovoltaic solar cells each electrically connected to the printed circuit board, and a front sheet comprising a layer of plastic. The printed circuit board, the photovoltaic solar cells, and the layer of plastic can be at least part of a laminated structure attachable to the roof tile. The layer of plastic can be a layer of transparent, UV-resistant plastic. The layer of plastic can be a layer of ethylene tetrafluoroethylene. A method of manufacture of a photovoltaic solar panel for attachment to a roof tile can include forming a laminated structure by laminating one or more sheets that include a printed circuit board, a plurality of photovoltaic solar cells, and a front sheet. The front sheet can include a layer of plastic that can include ethylene tetrafluoroethylene.

FIELD OF THE INVENTION

The present invention relates to a photovoltaic solar panel.

BACKGROUND OF THE INVENTION

Photovoltaic solar panels are known which absorb solar and ultra violetrays, transforming them into electrical energy.

Referring to FIG. 1 herein, there is illustrated schematically inperspective view an installation comprising a plurality of known solarroof tiles, integrated into an existing concrete tile roof. Each solarroof tile has a width of approximately 3 concrete roof tiles. To installthe solar roof tiles, rows of individual roof tiles are removed, and thesolar roof tiles are fitted to the rafters of the roof in place of theconcrete roof tiles. Electrical connections to the solar roof tiles arepassed through the water proof membrane of the roof, and the electricalconnectors at the rear of each roof tile are connected into anelectrical circuit within the loft of the roof. Alternatively, theelectrical connectors can be connected together on top of the waterimpermeable membrane, and routed to the edge of the roof, so that asingle electrical cable is fitted outside the building down to anelectrical junction box at ground level.

Referring to FIG. 2 herein, there is illustrated schematically indetail, part of a solar roof tile as shown in FIG. 1 herein. The solarroof tile comprises a relatively thick sheet of substrate 200, forexample made of a plastic sheet, of a thickness similar to the thicknessof the adjacent concrete tiles. On top of the plastic substrate, arepositioned a plurality of substantially square solar panels 201. On topof the solar panels, is positioned a glass or plastics cover sheet 202,which is held to the plastic substrate by a plurality of external clips203 around the edges of the clear transparent plastics sheet.

Referring to FIG. 3 herein, there is illustrated schematically inperspective view, a pair of solar tiles as shown in FIGS. 1 and 2.

Referring to FIG. 4 herein, there is illustrated schematically in crosssectional view part of a known photovoltaic solar panel. The solar panel400 comprises a back sheet 401; first and second encapsulation layers402, 403; a photovoltaic cell 404; and an ultra-violet resistant glassor plastic screen front sheet 405, which protects the panel againstmechanical impact and weathering.

The back sheet portion 401, of the photovoltaic solar panel 400comprises two surfaces 406, 407, wherein the first surface 406 may beattached to the surface of a roof tile. The second surface of the backsheet portion 407 is adjacent to a first surface 408 of encapsulationlayer 402; and a second surface 409 of first encapsulation layer 402 isin adjacent contact with the photovoltaic cell 404. The photovoltaiccell is also in adjacent contact with a first surface 410 of secondencapsulation layer 403; and a second surface 411 of secondencapsulation layer 403 is in adjacent contact with a first surface 412of the front sheet 405.

The term “adjacent contact with” does not necessarily mean that thesecond surface of the encapsulation layer s in contact with a surface ofthe photovoltaic cell. A layer of encapsulation material may be usedbetween the photovoltaic cell and the back sheet 401 and/or the frontsheet 405

Polyethylene terephthalate PET is a known encapsulation material, whichis used in solar panels to bond front and back sheets of the paneltogether by the process of lamination.

Lamination of solar cells with polyethylene-vinyl acetate films isconducted at about 150° C., and permits molten polyethylene-vinylacetate to flow into voids in a solar panels to encapsulate the solarcell.

The current lifespan of PET solar panels is in the region of 5 to 10years.

Known photovoltaic panels do not integrate well into the architecture ofolder, traditional buildings.

SUMMARY OF THE INVENTION

It is an object of the current invention to increase the efficiency andlifespan of current solar panels whilst providing a photovoltaic solarpanel which can be easily integrated into various architecturalsurroundings.

According to a first aspect of the present invention, there is provideda photovoltaic solar panel for attachment to a roof tile configured witha through aperture, the panel comprising:

a rigid back plate;

a support sheet comprising at least one photovoltaic solar cell;

a negative and a positive connection extending from the or each solarcell through a sealed aperture of the back plate and accessible at therear of the panel;

a diode connected to the positive connection;

an ultra-violet resistant front sheet for covering a front face of theor each solar cell;

wherein the back plate, support sheet and front sheet form a sealedlaminated structure.

Other aspects of are as recited in the claims herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention and to show how the same maybe carried into effect, there will now be described by way of exampleonly, specific embodiments, methods and processes according to thepresent 30 invention with reference to the accompanying drawings inwhich:

FIG. 1 show schematically a known solar tile in a roof installation;

FIG. 2 shows schematically a detail of the known solar tile of FIG. 1herein;

FIG. 3 shows schematically two known solar tiles prior to installationin a roof;

FIG. 4 is a schematic cut away view of a known photovoltaic solar panel;

FIG. 5 illustrates schematically a first embodiment solar panel and rooftile in exploded view;

FIG. 6 illustrates schematically in view from the front, a solar panelcomprising the first embodiment solar tile;

FIG. 7 is an exploded view of a second embodiment photovoltaic solarpanel and roof tile;

FIG. 8 is an enlarged view of a printed circuit board of the solar tileof FIG. 7 herein;

FIG. 9 is a perspective view of a cross-section taken along line ‘A’ inof the circuit board of FIG. 8;

FIG. 10 is a perspective view of an improved solar roof tileincorporating a solar panel disclosed herein;

FIG. 11 is a plan view of the improved solar roof tile of FIG. 10herein;

FIG. 12 is a cross-section along plane ‘C’ of FIG. 11;

FIG. 13 is a close up view of one end of FIG. 12 herein;

FIG. 14 is an illustration of one stage of a photovoltaic solar panelmanufacturing process;

FIG. 15 is an illustration of another stage of manufacture of thephotovoltaic solar panel;

FIG. 16 illustrates schematically in view from the front, a solar cellcomprising a solar panel described herein;

FIG. 17 illustrates schematically the solar cell of FIG. 16 in view fromthe rear; and

FIG. 18 illustrates schematically circuit diagram for connecting aplurality of solar roof tiles as described herein before in a solar roofpanel installation.

DETAILED DESCRIPTION OF THE EMBODIMENTS

There will now be described by way of example a specific modecontemplated by the inventors. In the following description numerousspecific details are set forth in order to provide a thoroughunderstanding. It will be apparent however, to one skilled in the art,that the present invention may be practiced without limitation to thesespecific details. In other instances, well known methods and structureshave not been described in detail so as not to unnecessarily obscure thedescription.

There is disclosed herein a novel photovoltaic solar panel designed tobe attached to the front face of proprietary concrete, clay, metal orplastic roof tile. The solar panel is capable of generating electricityand thus providing a solar tile. The solar tile may be fitted directlyto a roof to form a flat roof surface. The apparatus is designed to fitto new and replacement roofs.

Referring to FIG. 5 herein, there is illustrated schematically inexploded view a first embodiment solar tile incorporating a novel solarpanel.

The roof the comprises a roof tile 500, which can be a cement, plasticsor metal roof tile. The solar panel comprises a silicone based adhesivesealant layer 501; a fiber glass back plate 502; a sheet 503 comprisinga one or a plurality of monocrystalline or polycrystalline solar cellseach comprising one or more solar wafers; and an ultra-violettransparent plastics cover sheet 504.

The one or more solar cells are sandwiched between the clear cover sheet504, on the side of the wafer which is exposed to sun light, and thefiber glass back plate 502 at the rear side, which is adjacent the rooftile 500. The silicone based adhesive sealant layer 501 sticks a rearsurface of the fiber glass back plate 502 to a front surface of the rooftile 500. The fibre glass back sheet gives rigidity and support to thesheet 503 which contains the solar cells.

The solar panel further comprises electrical connections which areaccessible at the rear of the roof tile, for connecting the solar panelto an electrical circuit. The electrical connections comprise a negativeconnector 505; a positive connector 506; a silicone based seal 507,which fits into an aperture in the roof tile 500 and surrounds a pair ofpositive and negative conductors 508, 508 respectively such that theconnectors are spaced apart, and protected from the weather andmoisture; each electrical conductor 508, 500 comprising a copper wiresurrounded with an insulating plastic sheath; a diode 510 connected to apositive output of the solar cells 503 and to positive conductor 509;and first and second aluminum strips 511, 512 which respectively formelectrical connectors to the solar cells of the sheet 503, the aluminumstrips each being covered with a respective strip of insulatingelectrical tape, the first strip 511 being connected to the positiveconductor 509 via diode 510, and the second aluminum strip 512 beingconnected to the negative conductor 508.

The clear or transparent plastics cover sheet 504, the solar wafer sheet503, along with first and second aluminum strip conductors 611, 512, andthe fiber glass back plate 502 form a sealed laminated unit, which issealed against the ingress of moisture.

Referring to FIG. 6 herein, there is illustrated schematically infrontal view, an individual solar wafer. The solar wafer has generalcharacteristics as follows:

In the example shown, a Monocrystalline P type boron doped siliconesheet has dimensions 156 mm height by 156 mm width. The Monocrystallinesilicon wafer is grown by the CZ method. Electrical characteristics ofthe solar sheet are as follows:

Features General Characteristics Resistivity 1~3, 3~6 Ω · com OxygenContent 1 × 10 18 atom/cm3 Carbon Content 1 × 10 17 atom/cm 3 StructuralCharacteristics Side 156.0 mm ± 0.5 mm Diameter 200.0 mm ± 0.5 mmOrientation <100> Thickness 180 ± 20 μm 200 ± 20 μm MechanicalCharacteristics TTV ≤40 μm Bow ≤70 μm Surface No microcrystallinestructure Saw Mark ≤15 μm

Whilst FIG. 6 shows a best mode embodiment monocrystalline silicon solarwafer, variations to the dimensions may be applied in other embodiments.

Referring to FIG. 7 herein a second embodiment photovoltaic solar panel700, designed to be attached to the front surface of a roof tile 701,comprises a male plug DC connector 702, inserted from the front side ofthe tile; a female plug 703 located in a hole drilled through said tile;a printed circuit board 704; a junction box 705, permanently sealed tothe back of said circuit board; which houses a diode 706, which isconnected to positive and neutral wires 707, 708, extending from thefemale plug 703; said wires are in turn connected to the circuitry ofthe circuit board 704.

A solar array 709 is provided and consists of a plurality ofmonocrystalline solar wafers 710 which are connected together in a bankof two rows.

The junction box is rated at 1000 dcV.

Each solar wafer 710 is situated on a layer of ethylene-vinyl acetate711, which covers the surface of the printed circuit board 704.

Soldered aluminum strips 712 connect individual solar cells 710; theends of said strips are folded over the top of the cells 710 to attachthem to the circuit board 704.

The aluminum strips are covered by a strip of electrical tape and asheet of ethylene-vinyl acetate 713. A layer of ethylenetetrafluoroethylene 714 covers the ethylene-vinyl acetate 713.

The total layered array is bound via lamination at a temperature rangeof 150° C. to 200° C., a vacuum pressure of 2 to 4 atmospheres for aperiod of 10 to 15 minutes.

Referring to FIG. 8 herein, the printed circuit board 704 comprises asubstrate board 801, substantially rectangular in shape; negative andpositive electrical conductive tracks 802, 803; and an aperture 804which extends through 2 s the circuit board 704.

Referring to FIG. 9 there is shown a perspective view of a cross-sectiontaken along line ‘A’ in FIG. 8, wherein, the aperture through thecircuit board 704 is visible.

Referring to FIG. 10 herein there is shown a perspective view of a thirdembodiment improved solar roof tile and solar panel 1000, comprising asubstantially rectangular, flat roof tile 1001, with first and secondthrough tile apertures 1002, 1003, equidistant from a perimeter of thetile, and grooves 1004, 1005 on the extreme edges of the tile to enableattachment of the tile to a roof; and a substantially rectangularphotovoltaic solar panel 1006, fixed to a front face of the roof tilethe solar panel having area dimensions smaller than the area dimensionsof a front face of the roof tile.

FIG. 11 is a plan view of an improved solar roof tile and panel 1000,shown in FIG. 10 herein, comprising a substantially rectangular, flatroof tile 1001, with through tile apertures 1002, 1003, equidistant fromthe perimeter of the tile and grooves on the extreme edges of the tile1004 to enable attachment of the tile to a roof; and a substantiallyrectangular photovoltaic solar panel 1004, which is smaller than thedimensions of the roof tile.

Referring to FIG. 12 herein, there is shown a cross-section along plane‘C’ of FIG. 11 in which the height of the roof tile 1001 extends beyondthe height of the photovoltaic solar panel 1006, and in which the circleannotation denotes that the degree of overlap between the tile and thephotovoltaic solar panel is variable and determined by the manufacturer.

Referring to FIG. 13 herein, in close up detail part of the crosssection of FIG. 12, showing the laminate structure of the solar panelaffixed to the front of the roof tile.

Referring to FIG. 14 herein, there is illustrated a view of one stage ofa manufacturing process for making a solar panel and roof tile asdescribed herein, in which a plurality of mono crystalline solar wafers1401 are arranged on a circuit board 1402, on a layer of ethylene-vinylacetate and are connected together by soldered aluminum wires 1402, in abank of two rows. The soldered aluminum wires 1402 are covered by stripsof electrical tape.

Referring to FIG. 15 herein, there is illustrated another manufacturingstage for manufacture of a solar panel as described herein. Each of aplurality of solar wafers 1500 in a row are connected together with analuminum strip electrical connector 1501. The aluminum strip connectoris covered with a strip of black electrically insulating and protectivetape 1502.

Referring to FIG. 18 herein, there is illustrated schematically anindividual solar wafer, having first and second electrical conductors1601, 1602.

Referring to FIG. 17 herein, there is illustrated schematically thereverse side of the solar wafer shown in FIG. 16.

Referring to FIG. 18 herein, there is illustrated schematically a wiringdiagram for connection of a plurality of individual solar roof panels ina solar roof tile installation.

An array of individual solar roof panels 1800 are arranged in rows andcolumns on a roof. Each individual solar panel has a positive conductorand a negative conductor as shown in FIGS. 5, 7 and 8 herein, with adiode on the positive conductor, so that when a negative conductor of afirst solar panel is connected to a positive conductor of a second solarpanel in a serial chain, there is a single one-way D.C. electrical pathflowing through a chain of solar cells in series. The plurality ofsemi-conductor diodes ensure that current can flow in only one directorthrough the chain of serially linked solar panels.

In FIG. 18, there are shown individual chains of solar panels 1801 to1815. A respective positive terminal of each chain of solar panels areconnected together to form a positive bus 1816, and similarly, arespective negative terminal of each chain of solar panels are connectedtogether to form a 30 negative bus 1817. The positive and negative busessupply current, via a direct current circuit breaker 1818, to an ACinverter, which converts the direct current output of the solar cellsinto a single phase alternating current electrical output. There isprovided a surge protector 1820 which connects to earth, so that in theevent of a high voltage or current spike experienced on the negativebuses, these are grounded to earth. This provides protection fromcurrent and/or voltage surges during for example an electrical storm.

Conventional roof tile dimensions from different manufacturers vary. Theheight and width of the solar panel embodiments disclosed herein may beselected to match the size of roof tile. A minimum length and width ofeach panel is calculated to produce a minimum of 10 Watts each at peaksunlight, and is dependent on the available area of the roof tile. Mostknown roof tile areas will achieve this minimum power output. Largersized roof tiles allow the solar cell area to be increased, achieving agreater power output.

Each solar panel contains a diode on the positive circuit of its printedcircuit board. Each solar tile is fitted to a roof using a known roofingmethod. The solar tiles are wired together in series to form a solararray. The solar array is connected through a combiner box and to aninverter.

The output of the solar array is dependent on the D.C. voltage rangedemanded by the inverter. The voltage is controlled by limiting thenumber of solar tiles wired in series. Each series or row of solar tileshas two final contact wires which are combined together through asuitable fuse to a positive and negative bus bar to form a parallelcircuit with one positive and one negative output. These outputs arewired to an inverter.

Each solar cell within the solar panel is protected by an electricaldiode within the series circuitry to minimize the effect of “shadowing”for example as the incident light on the solar cells vary due to cloudmovements. If one solar cell is shadowed, its performance is reducedwithout affecting the performance of any adjacent solar cell. Similarly,if one solar panel is shaded by for example a tree, then its performancemay be reduced compared to an adjacent solar panel which is in fullsunlight. Due to the serial diodes, the shading of one solar cell doesnot affect the performance of adjacent solar cells.

The embodiments disclosed herein can be fitted to new or replacementroofs. Any individual failed solar panel is easily replaceable by a newsolar roof tile.

1-28. (canceled)
 29. A photovoltaic solar panel comprising: a printedcircuit board; a plurality of photovoltaic solar cells each electricallyconnected to the printed circuit board; and a front sheet comprising alayer of plastic, wherein the printed circuit board, the photovoltaicsolar cells, and the front sheet are at least part of a laminatedstructure attachable to a roof tile.
 30. The photovoltaic solar panel ofclaim 29, wherein the layer of plastic is a layer of transparent,UV-resistant plastic.
 31. The photovoltaic solar panel of claim 29,wherein the layer of plastic is a layer of ethylene tetrafluoroethylene.32. The photovoltaic solar panel of claim 29, the photovoltaic solarpanel further comprising: a first layer of ethylene-vinyl acetatecovering at least a surface of the printed circuit board; and a secondlayer of ethylene-vinyl acetate covering the photovoltaic solar cells,wherein the first layer and the second layer are at least part of thelaminated structure attachable to the roof tile.
 33. The photovoltaicsolar panel of claim 32, wherein the layer of plastic covers a frontsurface of the second layer of ethylene-vinyl acetate.
 34. Thephotovoltaic solar panel of claim 29, the photovoltaic solar panelfurther comprising a rigid back plate.
 35. The photovoltaic solar panelof claim 34, further comprising an adhesive sealant layer in adjacentcontact with the rigid back plate, the adhesive sealant layer adherableto the roof tile.
 36. The photovoltaic solar panel of claim 29, whereinthe printed circuit board, the photovoltaic solar cells, and the frontsheet are at least part of a laminated structure attachable to a rooftile, the roof tile which comprises at least one of concrete, clay,metal, and plastic.
 37. The photovoltaic solar panel of claim 29,wherein the photovoltaic solar panel is substantially rectangular andhas area dimensions smaller than the area dimensions of a front face ofthe roof tile.
 38. A method of manufacture of a photovoltaic solar panelfor attachment to a roof tile, the method comprising forming a laminatedstructure by laminating one or more sheets that include a printedcircuit board, a plurality of photovoltaic solar cells, and a frontsheet, wherein laminating a front sheet includes laminating a layer ofplastic.
 39. The method of manufacture of claim 38, wherein laminating alayer of plastic includes laminating a layer of transparent,UV-resistant plastic.
 40. The method of manufacture of claim 38, whereinlaminating a layer of plastic includes laminating a layer of ethylenetetrafluoroethylene.
 41. The method of manufacture of claim 38, whereinlaminating one or more sheets to form a laminated structure furtherincludes laminating a first layer of ethylene-vinyl acetate covering atleast a surface of the printed circuit board, and laminating a secondlayer of ethylene-vinyl acetate covering the photovoltaic solar cells.42. The method of manufacture of claim 41, wherein laminating a layer ofplastic includes laminating a layer of plastic to cover a front surfaceof the second layer of ethylene-vinyl acetate.
 43. The method ofmanufacture of claim 38, wherein forming a laminated structure bylaminating one or more sheets includes laminating a rigid back plate.44. The method of manufacture of claim 43, the method further comprisingapplying an adhesive sealant layer in adjacent contact with the rigidback plate, the adhesive sealant layer adherable to the roof tile. 45.The method of manufacture of claim 44, wherein applying an adhesivesealant layer in adjacent contact with the rigid back plate includesapplying an adhesive sealant layer adherable to a roof tile, the rooftile which comprises at least one of concrete, clay, metal, and plastic.46. The method of manufacture of claim 38, wherein forming a laminatedstructure by laminating one or more sheets that include a printedcircuit board, a plurality of photovoltaic solar cells, and a frontsheet includes forming a laminated structure that is substantiallyrectangular and has area dimensions smaller than the area dimensions ofa front face of the roof tile.